Meeting Abstract
The movement of the Indian Subcontinent is a key issue in determining Gondwanan biogeographic patterns. Its position between Africa, Madagascar, and Eurasia raises questions about its geographical situation, the dates of its rifting and collision with Eurasia, and its role in dispersal events. India has been proposed as a biotic ferry which introduced African and Madagascan fauna to Asia, but it is still debated whether India was in isolation or close proximity to Southeast Asia during its journey northward. Harvestmen of the family Assamiidae (Opiliones: Laniatores) are an excellent system to address these events and vicariance hypotheses. This highly variable group of animals (2-8mm in body length) can be found throughout Africa, India, and Australasia, but is intriguingly absent from Madagascar and the Seychelles. In order to (a) test the monophyly of Assamiidae, (b) clarify the relationships between African and Asian taxa, and (c) compare the timing of continental collision and the diversification of Southeast Asian lineages, we inferred the phylogeny of the family for the first time using a multilocus dataset. We sequenced 141 terminals collected from Africa, Southeast Asia, and the Southwest Pacific for six markers known to be informative in arachnid systematics: two mitochondrial loci (16S rRNA and cytochrome c oxidase subunit I), and four nuclear loci (histones H3 and H4, 18S rRNA, and 28S rRNA). We performed maximum likelihood analysis in RAxML and Bayesian inference analysis in MrBayes. To distinguish between competing biogeographic hypotheses, we inferred divergence dates using BEAST and reconstructed ancestral areas using the R package BioGeoBEARS. Here we present the first molecular phylogeny of Assamiidae and a reconstruction of their biogeographic history, toward understanding the origins of Southeast Asian arachnofauna.
